Aberrantly elevated adenosine in the tumor microenvironment exerts its immunosuppressive functions through adenosine receptors A_2AR and A_2BR. Antagonism of A_2AR and A_2BR has the potential to suppress tumor growth. Herein, we report a systemic assessment of the effects of an indole modification at position 4, 5, 6, or 7 on both A_2AR/A_2BR activity and selectivity of novel 2-aminopyrimidine compounds. Substituting indole at the 4-/5-position produced potent A_2AR/A_2BR dual antagonism, whereas the 6-position of indole substitution gave highly selective A_2BR antagonism. Molecular dynamics simulation showed that the 5-cyano compound 7ai had a lower binding free energy than the 6-cyano compound 7aj due to water-bridged hydrogen bond interactions with E169 or F168 in A_2AR. Of note, dual A_2AR/A_2BR antagonism by compound 7ai can profoundly promote the activation and cytotoxic function of T cells. This work provided a strategy for obtaining novel dual A_2AR/A_2BR or A_2BR antagonists by fine-tuning structural modification.

中文翻译：

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A2AR/A2BR 双重拮抗作用和 A2BR 拮抗作用之间的微妙结构变化：一类新型 2-氨基嘧啶衍生物

肿瘤微环境中异常升高的腺苷通过腺苷受体A _2A R 和A _{2B R 发挥其免疫抑制功能。A 2A} R 和A _2B R的拮抗作用具有抑制肿瘤生长的潜力。在此，我们报告了4、5、6或7位吲哚修饰对新型2-氨基嘧啶化合物A _2A R/A _2B R活性和选择性影响的系统评估。在4-/5-位取代吲哚产生有效的A _2A R/A _2B R双重拮抗作用，而6-位吲哚取代则产生高度选择性的A _2B R拮抗作用。分子动力学模拟表明，由于与 A _2A R中的 E169 或 F168 存在水桥氢键相互作用，5-氰基化合物7ai 的结合自由能低于 6-氰基化合物 7aj 。值得注意的是，双 A _2A R/A化合物7ai对_2B R的拮抗作用可以深刻促进T细胞的活化和细胞毒功能。这项工作提供了一种通过微调结构修饰获得新型双重 A _2A R/A _2B R 或 A _{2B R 拮抗剂的策略。}